The present invention relates to fiber-reinforced plastic (FRP) bearing thereon a composition that is suitable as a base coat in compression molding applications.
In-mold coating (IMC) compositions can be applied to FRP to provide a smooth surface and to reduce or eliminate substrate porosity. However, such coatings generally require painting to yield desirable end use properties.
A typical IMC composition involves the reaction product of an unsaturated'fumarate polyester diol, a saturated polyester diol flexibilizer, a crosslinking aliphatic polyol having from 3 to 6 hydroxyl groups, a diisocyanate, and an ethylenically unsaturated crosslinking compound such as styrene; see, e.g., U.S. Pat. Nos. 4,189,517 and 4,222,929.
Other approaches are described in, for example, U.S. Pat. Nos. 4,331,735, 4,414,173, 4,515,710, and 5,084,353.